I recently purchased destiny the legendary edition (physical copy) which has all the add on content and what not. I downloaded all of the stuff and codes in the case to my playstation and was playing fine. My little brother got a hold of the disc copy and managed to crack it :(. Now it no longer works. My question is if i buy just a used disc copy of destiny will the add ons still work?
Yes all the DLC will still work with any copy of Destiny, Digital or a Physical disc.
The copy of Destiny that comes with the Legendary Edition is actually the same disc as the regular edition that launched a year ago.
Source: Personal experience, I traded my launch day copy of Destiny for The Taken King Legendary Edition. The disc was the same but the DLC download codes were included in the box.